java学习之路----IO----合并流和文件操纵流

 在IO中提供了两个与平台无关的数据操纵流，一个是数据输出流（DataOutputStream）,一个是数据输入流(DataInputStream)

               

1.DataOutputStream例子

public class DataOutputStreamDemo {

     public static void main(String[] args) throws Exception {

          File f = new File("f:" + File.separator + "a.txt");

          DataOutputStream dos = new DataOutputStream(new FileOutputStream(f));

          

          String names[]={ "衬衣","手套" ,"围巾" };

           float prices[]={93.9f,85.9f,12,3f};

           int nums[]={3,2,1};

           for(int i=0;i<names.length;i++){

              dos.writeChars(names[i]);

              dos.writeChars( "\t");

              dos.writeFloat(prices[i]);

              dos.writeChars( "\t");

              dos.writeInt(nums[i]);

              dos.writeChars( "\n");

          }

          

          dos.close();

     }

}

2.在从a.txt里面读出来

     public class DataInputStreamDemo {

           public static void main(String[] args) throws Exception{

              File f= new File("f:"+File.separator +"a.txt" );

              

              DataInputStream dis= new DataInputStream(new FileInputStream(f));

              

               char temp[]=new char[200];

              

               int len=0;

              

              String name= null;

              

               int num=0;

              

               float price=0.0f;

              

               char c=0;

               try{

               while(true ){

                         while((c=dis.readChar())!='\t' ){

                             temp[len]=c;

                             len++;

                        }

                        name= new String(temp,0,len);

                        

                        price=dis.readFloat();

                        dis.readChar();

                        num=dis.readInt();

                        dis.readChar();

                        System. out.printf("名称：%s,价格:%5.2f,数量:%d\n" ,name,price,num);

              }

              } catch (Exception e) {

                    // TODO: handle exception

              }

              dis.close();

          }

}

价格：

名称：衬衣,价格:93.90,数量:3

名称：衬衣手套,价格:85.90,数量:2

名称：衬衣手套围巾,价格:12.00,数量:1

合并流的作用是把两个文件的内容合并到一起

          

public class SequenceDemo {

           public static void main(String[] args) throws Exception{

                   File f= new File("f:"+File.separator +"a.txt" );

                   File f1= new File("f:"+File.separator +"b.txt" );

                   File f3= new File("f:"+File.separator +"ab.txt" );

                   

                   InputStream io1= null;//输入流1

                   

                   InputStream io2= null;//输入流2

                   

                   OutputStream out= null;//输出流1

                   

                   SequenceInputStream sis= null;//合并流

                   

                   io1= new FileInputStream(f);

                   io2= new FileInputStream(f1);

                   

                   out= new FileOutputStream(f3);

                   

                   sis= new SequenceInputStream(io1, io2);

                    int temp=0;

                    while( (temp=sis.read())!=-1){

                        out.write(temp);

                   }

                   sis.close();

                   io1.close();

                   io2.close();

                   out.close();

                   

          }

}